It has previously been proposed to provide a screening system for the screening of sewage, sludges and industrial effluents which has a generally cylindrical screenings basket formed by a plurality of cylindrically curved, coaxial and axially spaced screen bars. Within the screenings basket, there is provided a trough, containing an conveyor auger, and a rake which is rotatable within the basket for raking screenings from the bars into the conveyor.
In operation of this prior art system, the cylindrical screenings basket is mounted at an inclination in a channel along which the mixture of liquid and solids flows towards the screenings basket and into an open end of the screenings basket. The inflowing liquid can then leave the basket through gaps between the cylindrically curved bars of the basket, whereas the solids are retained on these bars within the basket until they are raked by the rotating rake and thereby deposited into the trough for conveyance upwardly from the screenings basket by the conveyor auger to a compactor.
It is a disadvantage of this prior art system that, since the auger conveyor is coaxial with the cylindrical screenings basket, and since the latter must be disposed at a relatively low inclination in order to utilize the maximum area of the basket for screening, the auger must consequently be disposed at the same low angle of inclination. This prior art system is therefore bulky.